Cod sursa(job #2655700)
Utilizator | Cristea Cristian CristeaCristian | Data | 5 octombrie 2020 11:32:31 |
---|---|---|---|
Problema | Numarare triunghiuri | Scor | 100 |
Compilator | cpp-64 | Status | done |
Runda | Arhiva de probleme | Marime | 0.86 kb |
#include <fstream>
#include <algorithm>
using namespace std;
ifstream fin("nrtri.in");
ofstream fout("nrtri.out");
const int NMAX=800;
int v[NMAX+5];
int main()
{
int n,dr,st,med,i,j,s,last,rasp=0,k;
fin>>n;
for(i=1;i<=n;i++)
{
fin>>v[i];
}
sort(v+1,v+n+1);
for(i=1;i<n-1;i++)
{
for(j=i+1;j<n;j++)
{
s=v[i]+v[j];
dr=n;
st=j+1;
last=-1;
while(st<=dr)
{
med=(st+dr)/2;
if(s>=v[med])
{
last=med;
st=med+1;
}
else
{
dr=med-1;
}
}
if(last!=-1)
rasp+=last-j;
}
}
fout<<rasp;
return 0;
}